Need help verifying a schematic diagram

I have a schematic diagram here.. i was wondering if some of the experienced guys over here could help me verify if this circuit would work if i were to build it. Its a rather simple circuit, here is the part list for the circuit and also the diagram... hope someone could give me some comments... thanks alot

C1 10nF ceramic disc capacitor

C2 100nF ceramic disc capacitor

C3 1000uF electrolytic capacitor

D1 1N4148 signal diode

D2 LED

Q1 BC327 TO-92 transistor

R1 10K 0.25W variable resistor

R2 1K 0.25W variable resistor

R3, R4 470R 0.5W resistor

U1 TL072 Op-amp

This circuit basically consists of P1 and P2 which are measurement rods driven into soil.. and a voltage will be indicated at the voltmeter attached at P3 and P4, potentiometer R1 is to adjust the range of the voltage so that it will be between the 15 v voltmeter. The op amp basically compares the value.. R2 is adjusted till the motor starts ( motor outputs are P6 and P5) the transistor amplifies the current to the motor, while the diode avoids the circuit from getting burnt from the motors inductance while the capacitors help smoother the circuits output